Pretty much every Republican told Trump not to impose tariffs. He did it anyway.

President Trump signed proclamations at the White House Thursday that establish new tariffs on steel and aluminum imports.

Analysis by Chris Cillizza CNN Editor-at-large

WASHINGTON (CNN) -- President Donald Trump has rarely been consistent about much of anything when it comes to politics and policy. He's been a Democrat, an independent and a Republican. He's been pro-choice and pro-life. He's favored more gun control and cast himself as the "biggest fan" of the Second Amendment in the country.

Except when it comes to trade. In the battle between protectionism and free trade, Trump has very consistently sided with those who express skepticism about the move toward globalism in all things. The idea of putting America first, and looking out for our country before we worry about anyone else, has long been part of Trump's patter -- way before he ever even considered running for president.

Which brings us to Thursday afternoon at the White House, when Trump signed a measure instituting a 25% tariff on imported steel and a 10% tariff on imported aluminum.

"The American steel, aluminum industry has been ravaged by aggressive foreign trade practices," Trump said in the Roosevelt Room. "It's really an assault on our country. It's been an assault."

He instituted the tariffs in spite of widespread opposition in his party. "It's still all bad," said John Thune (South Dakota), the third-ranking Republican in the Senate, just before Trump's signing ceremony. "There isn't anything about this that's going to turn out well for us."

And it wasn't just hot rhetoric coming from the Republicans who opposed the measure. Trump's support for the tariffs cost him his top economic adviser in Gary Cohn, who resigned earlier this week following the President's decision to push forward with the tariffs.

So why did Trump do it? Because -- and this is a real rarity with Trump -- he believes it is the right thing to do. In fact, he is convinced of it.

The Point: Trump talked relentlessly about protecting the American worker during the campaign. Then he won. So no one -- including all the Republicans aghast at his decision on tariffs -- should be surprised in the least. This is -- gasp -- Trump making good on a long-held and long-stated belief.